Problem in datasource of Project systems 0PS_C04

Hi,

i m extracting the data for 0ps_c04 but m not getting data for most of the data sources as i checked in R/3 data is not available where i checked the data in the various tables used like

data source 0CO_OM_NAE_1

using function module BWPS_GET_NAECST

using tables like COSP COSS COSEL these tables are having data but this data is showing 0 data.

and this is happening with most of the datasources.

plz leetme know wt cud be the reason.

Do we need for some settings before extracting data to PS cubes as we do delete setup tables .

thnx in advance